How to find a particular application port number ?

@Mohit: That was a good question. I searched for it and found this answer:

1. Press Ctl+Alt+Del to open the Task Manager (on some systems you may have to click the Task Manager button)

2. In Task Manager, click View > Select Columns

3. Make sure the PID (Process Identifier) checkbox is checked and press OK

4. Click the Processes tab, then scroll through the list and find the application you are looking for. Make note of the PID next to it.

5. Open command prompt: clcik Start > then click Run > type in "CMD" and press enter (a black command prompt should open)

6. Type in " netstat -o -n" and press enter*
*You can also add "-a" to the command to have it show more port information (all applications and listening ports)

7. Find the item in the list that has the same PID as you noted above.

8. To find the port, look at the under the Foreign Address column and make note of the number after the colon.*

*This is typically called a socket and is in the format IP.add.re.ss: portNumber. For Google talk this was 72.14.253.125:443 - meaning that the port number was 443 (which happens to be the default port for SSL connections).

Thanks for the reply AKD.
I looked and found some states like
Time_wait closed_wait and established.Can you tell me why these states stand for...?
Always pid(process id) of the time_wait is 0.Can you tell me why PID of time_wait states is 0 ?